Pulley and shaft assembly for rotary lawn mower

ABSTRACT

A cylindrical sleeve for a lawn mower drive shaft is formed from two hollow tubes each of which has an inturned annular flange on one end thereof. An annular collar for supporting the sleeve is placed between theinturned flanged ends of the two tubes and a hollow rivet is passed through the inturned flanges and the inner periphery of the annular collar. The rivet is headed to secure the two inturned flanges and the supporting collar tightly together, thereby forming a cylindrical sleeve having a supporting collar intermediate the ends thereof. A drive shaft is journalled within the cylindrical sleeve and a saddle for the lawnmower blade is welded to one end of the drive shaft, and a drive pulley to the other end.

1 1 Oct. 2, 1973 1 PULLEY AND SHAFT ASSEMBLY FOR ROTARY LAWN MOWER [75]Inventors: William W. Steil, Wauwatosa', Bryan E. Domin, Hales Corners,both of Wis.

[73] Assignee: Production Stamping Corporation, Milwaukee, Wis.

[22] Filed: June 23, 1972 [21] Appl. No.: 265,720

2,734,327 2/1956 Whittney 56/255 909,506 1/1909 Zimmerer... 74/230.81,352,829 9/1920 Nelson 74/230.8

Primary Examiner-Charles J. Myhre Assistant ExaminerR. l-l. LazarusAttorney-Arthur L. Morsell, Jr.

[57] ABSTRACT A cylindrical sleeve for a lawn mower drive shaft isformed from two hollow tubes each of which has an inturned annularflange on one end thereof. An annular collar for supporting the sleeveis placed between theinturned flanged ends of the two tubes and a hollowrivet is passed through the inturned flanges and the inner periphery ofthe annular collar. The rivet is headed to secure the two inturnedflanges and the supporting collar tightly together, thereby forming acylindrical sleeve having a supporting collar intermediate the endsthereof. A drive shaft is journallcd within the cylindrical sleeve and asaddle for the lawnmower blade is welded to one end of the drive shaft,and a drive pulley to the other end.

7 Claims, 9 Drawing Figures PULLEY AND SHAFT ASSEMBLY FOR ROTARY LAWNMOWER BACKGROUND OF THE INVENTION This invention relates to pulley andshaft assemblies for the mower blades of rotary lawn mowers, and is usedin that type of mower where a drive shaft extends rotatably through thetop of the mower housing, there being a pulley for a belt drive at theupper end of the shaft above the mower housing, and there being a saddlefor the mower blade at the lower end of the shaft below the mowerhousing.

Heretofore in the manufacture of pulley and shaft assemblies for theabove-noted type of lawn mower, the pulley and blade saddle have beenconnected to their respective ends of the shaft with drive pins, and theshaft has been suitably supported for rotation through an opening in thetop of the mower housing. This type of assembly is expensive tomanufacture in that there is considerable labor involved in connectingthe blade saddle and pulley to the shaft with drive pins and inperforming the other assembly steps.In my co-pending applicaiton Ser.No. 173,982, now US. Pat. No. 3,727,475 it is proposed to have the driveshaft journalled in a sleeve having an annular bulge intermediate thetwo ends thereof, a supporting collar for securing the sleeve to thelawn mower housing being friction welded to the annular bulge. With thepresent invention, however, it has been found that improvedcharacteristics and lower costs can be achieved.

Accordingly, the principal object of this invention is to provide apulley and shaft assembly which has improved characteristics and lowercost.

An additional object of this invention is to provide a pulley and shaftassembly in which the sleeve supporting the shaft is made from twotubes, each of which has an inturned annular flange on the end thereof,the tubes being held together by a hollow rivet which also secures asupporting collar between the two annular flanges.

A further object of this invention is to provide a pulley and shaftassembly of the above-noted character which is sturdy in structure andreliable in operation.

SUMMARY OF THE INVENTION In accordance with this invention, theabove-noted objects are attained by providing two hollow tubes, each ofwhich has an inturned annular flange on one end thereof. An annularcollar for supporting the tubes is placed between the inturned annularflanges of the two tubes and a hollow rivet is passed through the in-BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a sheet metalblank which is to be deep drawn to form a tube having an inturnedannular flange on one end thereof;

FIG. 2 is a side view of a deep drawn tube with the top and bottomportion thereof being broken away and shown in cross-section;

FIG. 3 is a detail sectional view showing the bottom of the deep drawntube of FIG. 2 with an opening formed in the closed end thereof to forman inturned annular flange around said end;

FIG. 4 is a longitudinal sectional view of two tubes having inturnedannular flanges and having an annular supporting collar positionedbetween the flanges, there being a hollow rivet extending through theinturned annular flanges and the inner periphery of the supportingcollar;

FIG. 5 is a detail sectional view showing the central portion of theassembly of FIG. 4 with the hollow rivet headed over to secure theassembly together as an integral unit;

FIG. 6 is a side view of a drive shaft for a rotary lawn mower with ablade saddle welded to one end thereof and with a ball bearing assemblymounted on the drive shaft adjacent to the blade saddle;

FIG. 7 is a longitudinal sectional view of one illustrative embodimentof the invention in its completely assembled form;

FIG. 8 is an elevational view showing the embodiment of FIG. 7 attachedto a lawn mower housing with the pulley thereof engaged by a drive beltand with a rotary lawn mower blade attached to the saddle, the belt andhousing being shown in section; and

FIG. 9 is a fragmentary detail plan view taken upon the line 99 of FIG.8.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 7, oneillustrative embodiment of the invention includes a drive shaft 10 whichis journalled within a cylindrical sleeve 12 by means-of bearings l4 and16. The cylindrical sleeve 12 is made from two tubes 18 and 20, each ofwhich has an inturned annular flange. The inturned annular flanges 22and 24 are located on opposite sides of the inner periphery of asupporting collar 26 and the three units, i.e., the tubes 18 and 20 andthe collar 26, are secured together by means of a tubular rivet 28 whichextends through the openings of the annular flanges 22 and 24 andthrough the inner periphery of the supporting collar 26. Rivet 28 has apreformed head 29 on one end thereof and a swaged head 31 on the otherend thereof.

A drive pulley 30 is friction welded to one end of the drive shaft 10with a washer 32 being located between the pulley 30 and the bearing 14.A welding bead 34 is indicated between the end of the shaft 10 and thecentral portion of the pulley 30. At the other end of the shaft 10, asaddle 36 is friction welded to the end of the shaft 10 with a washer 38being located between the saddle 36 and the bearing 16. A welding bead40 is indicated between the saddle 36 and the end of the shaft 10. Atapped opening 42 is formed through the saddle 36 and into the end ofthe shaft 10 to receive a bolt which removably holds the lawn mowerblade 44 against the saddle 36 as shown in FIG. 8, there being a bolt 46which is screwed into the threaded opening 42. The supporting collar 26is attached to the lawn mower housing 48 by means of bolts 50 whichextend through openings 52 in the lawn mower housing 48 and throughmatching openings in the collar 26. A rectangular opening 54 is cut inthe lawn mower housing between bolt holes 52 and is long enough to admitthe saddle 36 through the long dimension thereof. The shaft 10 isadapted to be rotated by means of a drive belt 56 which extends betweenthe pulley 30 and a motor (not shown).

The tubes 18 and 20 which make up the cylindrical sleeve 12 arepreferably formed by a deep drawing operation on circular blanks such asthe blank 58 indicated in FIG. 1. FIG. 2 shows the first step in forminga tube 20. During the first drawing operation the tube 20 is cupped asshown in FIG. 2 and is expanded at the upper end as at 60 to form abearing seat. FIG. 3 shows the lower end of the tube 20 after the nextoperation in which a bottom opening 62 is cut in the bottom so as todefine an annular inturned flange 24 whose inner periphery forms themargin of the opening 62. A similar tube 18 (see FIG. 4) is formed bythe same operation, the tube 18 having an expanded end 64 for forming abearing seat.

The two tubes 18 and 20 are placed with their inturned annular flanges22 and 24 adjacent opposite sides of a supporting collar 26, and ahollow rivet having a head 29 is passed through the opening in thecenter of the assembly as shown in FIG. 4. The lower end of the rivet 28is then headed over as at 31 in FIG. 5 to hold tubes 18 and 20 togetherand form a cylindrical sleeve which has a supporting collar 26intermediate its ends.

FIG. 6 shows a drive shaft 10 having a saddle member 36 friction weldedto one end thereof and having a bearing 16 secured between a washer 38,which is adjacent to the weld bead 40, and a shoulder 68 on the shaft10. A portion 69 of reduced diameter to provide a shoulder 70 is formedat the other end of the shaft 10 for seating a bearing. In themanufacture of this embodiment of the invention, the shaft 10, bearing16, and saddle assembly 36 shown in FIG. 6 are passed through thetubular rivet 28 of the assembly shown in FIG. 5 and a bearing similarto the bearing 14 is thereafter slipped onto the shaft and seatedagainst the shoulder 70. A pulley 30 is thereafter welded to the end ofthe shaft 10 above the bearing.

Although it is preferable to make the tubes 18 and 20 by the deepdrawing process described above, they can also be formed by cutting offpieces from a length of tubular stock and spinning the end of each pieceto form the inturned annular flanges 22 and 24 and also to form thebearing seat on the opposite end of each tube.

Various other modifications of the above-disclosed structure will beapparent to those skilled in the art, and this invention includes allsuch modifications as may fall within the scope of the following claims.

What we claim is:

1. A pulley and shaft aassembly comprising two hollow tubes each havingan inturned annular flange formed at one end thereof forming the marginof an opening, which openings are aligned with each other, an annularsupporting collar having an outside diameter which is larger than theoutside diameter of said tubes and having an inside diameter which issmaller than the inside diameter of the tubes, said annular supportingcollar being positioned between said inturned annular flanges, a tubularrivet extending through the openings of said inturned annular flangesand through said annular supporting collar, heads formed on opposingends of said tubular rivet to hold said inturned annular flanges andsaid annular supporting collar together and thereby form a cylindricalsleeve having an annular supporting collar intermediate the endsthereof, a drive shaft journalled within said cylindrical sleeve andextending through said hollow rivet, a drive pulley welded to one end ofsaid drive shaft, and means welded to the other end of said drive shaftfor receiving a rotary lawn mower blade.

2. A pulley and shaft assembly as defined in claim 1 wherein the innerdiameters of said inturned annular flanges are substantially equal toeach other.

3. A pulley and shaft assembly as defined in claim 2 wherein the innerdiameter of said annular supporting collar is substantially equal to theinner diameters of said inturned annular flanges.

4. A pulley and shaft assembly as defined in claim 3 wherein the outsidediameter of said tubular rivet is slightly smaller than the innerdiameter of said inturned annular flanges and annular supporting collar.

5. A pulley and shaft assembly as defined in claim 1 wherein there arebearing assemblies at the ends of said sleeve and wherein said driveshaft is journalled through said bearing assemblies, the ends of saiddrive shaft being of reduced diameter to provide shoulders which serveas seats for said bearings, and the unflanged ends of said hollow tubesbeing expanded to provide seats for the outer periphery of saidbearings.

6. A method of manufacturing a rotary drive assembly for the blade of arotary lawn mower, said method comprising the steps of:

a. providing a drive shaft;

b. welding a blade holder to one end of said drive shaft;

0. providing inturned annular flanges on one end of each of two hollowtube portions with each flange defining a circular opening;

(1. providing support means with a circular opening of less size thanthe inner diameters of said tube portions;

e. positioning the flanged ends of the tube portions on opposite sidesof said opening in the support means whereby the axes of the openings inthe inturned flanges and support means are aligned;

f. inserting a hollow rivet through said aligned openings with its headengaging the inturned flange of one tube portion;

g. heading the opposite end of the rivet to clamp the support meansbetween the two inturned flanges;

h. inserting said drive shaft through the tube portions and hollow rivetwith the blade holder adjacent one end of the connected tube portions;and

i. attaching a drive pulley to the other end of said drive shaftadjacent the other end of the connected tube portions.

7. A method as defined in claim 6 and including the steps of:

a. forming reduced portions on opposite ends of the drive shaft toprovide shoulders spaced from said ends;

b. slipping a bearing assembly onto said reduced portion at one end ofthe drive shaft to seat against said shoulder prior to welding the bladeholder to said end;

c. similarly slipping a bearing assembly onto the reduced portion at theopposite end of the drive shaft; and

d. expanding the end of each tube portion which is opposite the end withthe inturned flange to provide external seats for said bearingassemblies.

1. A pulley and shaft aassembly comprising two hollow tubes each havingan inturned annular flange formed at one end thereof forming the marginof an opening, which openings are aligned with each other, an annularsupporting collar having an outside diameter which is larger than theoutside diameter of said tubes and having an inside diameter which issmaller than the inside diameter of the tubes, said annular supportingcollar being positioned between said inturned annular flanges, a tubularrivet extending through the openings of said inturned annular flangesand through said annular supporting collar, heads formed on opposingends of said tubular rivet to hold said inturned annular flanges andsaid annular supporting collar together and thereby form a cylindricalsleeve having an annular supporting collar intermediate the endsthereof, a drive shaft journalled within said cylindrical sleeve andextending through said hollow rivet, a drive pulley welded to one end ofsaid drive shaft, and means welded to the other end of said drive shaftfor receiving a rotary lawn mower blade.
 2. A pulley and shaft assemblyas defined in claim 1 wherein the inner diameters of said inturnedannular flanges are substantially equal to each other.
 3. A pulley andshaft assembly as defined in claim 2 wherein the inner diameter of saidannular supporting collar is substantially equal to the inner diametersof said inturned annular flanges.
 4. A pulley and shaft assembly asdefined in claim 3 wherein the outside diameter of said tubular rivet isslightly smaller than the inner diameter of said inturned annularflanges and annular supporting collar.
 5. A pulley and shaft assembly asdefined in claim 1 wherein there are bearing assemblies at the ends ofsaid sleeve and wherein said drive shaft is journalled through saidbearing assemblies, the ends of said drive shaft being of reduceddiameter to provide shoulders which serve as seats for said bearings,and the unflanged ends of said hollow tubes being expanded to provideseats for the outer periphery of said bearings.
 6. A method ofmanufacturing a rotary drive assembly for the blade of a rotary lawnmower, said method comprising the steps of: a. providing a drive shaft;b. welding a blade holder to one end of said drive shaft; c. providinginturned annular flanges on one end of each of two hollow tube portionswith each flange defining a circular opening; d. providing support meanswith a circular opening of less size than the inner diameters of saidtube portions; e. positioning the flanged ends of the tube portions onopposite sides of said opening in the support means whereby the axes ofthe openings in the inturned flanges and support means are aligned; f.inserting a hollow rivet through said aligned openings with its headengaging the inturned flange of one tube portion; g. heading theopposite end of the rivet to clamp the support means between the twointurned flanges; h. inserting said drive shaft through the tubeportions and hollow rivet with the blade holder adjacent one end of theconnected tube portions; and i. attaching a drive pulley to the otherend of said drive shaft adjacent the other end of the connected tubeportions.
 7. A method as defined in claim 6 and including the steps of:a. forming reduced portions on opposite ends of the drive shaft toprovide shoulders spaced from said ends; b. slipping a bearing assemblyonto said reduced portion at one end of the drive shaft to seat againstsaid shoulder prior to welding the blade holder to said end; c.similarly slipping a bearing assembly onto the reduced portion at theopposite end of the drive shaft; and d. expanding the end of each tubeportion which is opposite the end with the inturned flange to provideexternal seats for said bearing assemblies.